Particle beam systems, such as scanning electron microscopes, are typically used during integrated circuit fabrication for a variety of purposes. Some particle beam systems are used for etching layers of material on the substrates on which the integrated circuits are formed, others are used for depositing material onto the surface of the substrate, and others still—such as scanning electron microscopes—are used for inspection of the integrated circuits.
Particle beam systems typically operate by accelerating a charged species, such as an electron, positron, or proton, toward a target of some sort. In the example of an electron microscope, electrons are accelerated toward an inspection sample, and detection of the resultant scattering of secondary electrons is used to resolve images of the sample, or to determine the chemical composition of the sample.
Particle beam systems make use of a low pressure, or high vacuum, area that is formed around the sample. The high vacuum area is typically formed within a chamber that encompasses both the sample itself, and a movable stage upon which the sample resides. The high vacuum environment is important for the proper operation of the particle beam system. Further, the ability to move the sample, such as on the movable stage, also tends to be important to the convenient operation of the system.
However, providing a vacuum chamber of a sufficient size to contain the entire sample and movable stage adds cost, complexity, and size to the particle beam system.
What is needed, therefore, is a system that overcomes problems such as those described above, at least in part.